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A common model of robustness of a graph against random failures has all vertices operational, but the edges independently operational with probability $p$. One can ask for the probability that all vertices can communicate ({\em all-terminal…

Combinatorics · Mathematics 2023-06-07 Jason I. Brown , Isaac McMullin

A graph with vertex set V and edge set E is called a (d,c)-expander if the maximum degree of a vertex is d and, for every subset W of V that has cardinality at most |V|/2, the number of edges between vertices in W and vertices outside of W…

Combinatorics · Mathematics 2007-05-23 Lars Engebretsen

Given a class $\mathcal G$ of graphs, let ${\mathcal G}_n$ denote the set of graphs in $\mathcal G$ on vertex set $[n]$. For certain classes $\mathcal G$, we are interested in the asymptotic behaviour of a random graph $R_n$ sampled…

Combinatorics · Mathematics 2022-09-22 Colin McDiarmid

A class of graphs is bridge-addable if given a graph $G$ in the class, any graph obtained by adding an edge between two connected components of $G$ is also in the class. The authors recently proved a conjecture of McDiarmid, Steger, and…

Combinatorics · Mathematics 2021-09-06 Guillaume Chapuy , Guillem Perarnau

A {\em faithful (unit) distance graph} in $\mathbb{R}^d$ is a graph whose set of vertices is a finite subset of the $d$-dimensional Euclidean space, where two vertices are adjacent if and only if the Euclidean distance between them is…

Combinatorics · Mathematics 2017-12-01 Noga Alon , Andrey Kupavskii

A natural problem in combinatorial rigidity theory concerns the determination of the rigidity or flexibility of bar-joint frameworks in $\mathbb{R}^d$ that admit some non-trivial symmetry. When $d=2$ there is a large literature on this…

Combinatorics · Mathematics 2025-09-30 Sean Dewar , Georg Grasegger , Eleftherios Kastis , Anthony Nixon

Let $G$ be a graph on $n$ nodes. In this note, we prove that if $G$ is $(r+1)$-vertex connected, $1 \leq r \leq n-2$, then there exists a configuration $p$ in general position in $R^r$ such that the bar framework $(G,p)$ is universally…

Metric Geometry · Mathematics 2014-08-18 A. Y. Alfakih

Sidorenko's Conjecture asserts that every bipartite graph H has the Sidorenko property, i.e., a quasirandom graph minimizes the density of H among all graphs with the same edge density. We study a stronger property, which requires that a…

Combinatorics · Mathematics 2019-12-10 Daniel Král' , Taísa Martins , Péter Pál Pach , Marcin Wrochna

We define the class of high dimensional graph manifolds. These are compact smooth manifolds supporting a decomposition into finitely many pieces, each of which is diffeomorphic to the product of a torus with a finite volume hyperbolic…

Differential Geometry · Mathematics 2016-03-22 Roberto Frigerio , Jean-Francois Lafont , Alessandro Sisto

For any metric $d$ on $\mathbb{R}^2$, an ($\mathbb{R}^2,d$)-geometric graph is a graph whose vertices are points in $\mathbb{R}^2$, and two vertices are adjacent if and only if their distance is at most 1. If $d=\|.\|_{\infty}$, the metric…

Combinatorics · Mathematics 2016-10-26 Huda Chuangpishit , Jeannette Janssen

Networks are inherently vulnerable to vertex failures, making the analysis of their structural robustness a fundamental problem in graph theory. In this study, we investigate the closeness and vertex residual closeness of graphs, with a…

Discrete Mathematics · Computer Science 2026-04-14 Hande Tuncel Golpek , Mehmet Ali Bilici , Aysun Aytac

For random $d$-regular graphs on $N$ vertices with $1 \ll d \ll N^{2/3}$, we develop a $d^{-1/2}$ expansion of the local eigenvalue distribution about the Kesten-McKay law up to order $d^{-3}$. This result is valid up to the edge of the…

Probability · Mathematics 2021-07-06 Roland Bauerschmidt , Jiaoyang Huang , Antti Knowles , Horng-Tzer Yau

Let $\mathcal{F}$ be a family of fixed graphs and let $d$ be large enough. For every $d$-regular graph $G$, we study the existence of a spanning $\mathcal{F}$-free subgraph of $G$ with large minimum degree. This problem is well-understood…

Combinatorics · Mathematics 2016-12-12 Guillem Perarnau , Bruce Reed

We prove a `resilience' version of Dirac's theorem in the setting of random regular graphs. More precisely, we show that, whenever $d$ is sufficiently large compared to $\varepsilon>0$, a.a.s. the following holds: let $G'$ be any subgraph…

Combinatorics · Mathematics 2020-06-25 Padraig Condon , Alberto Espuny Díaz , António Girão , Daniela Kühn , Deryk Osthus

The dimension of a graph $G$ is the smallest $d$ for which its vertices can be embedded in $d$-dimensional Euclidean space in the sense that the distances between endpoints of edges equal $1$ (but there may be other unit distances).…

Combinatorics · Mathematics 2020-02-25 Nóra Frankl , Andrey Kupavskii , Konrad J. Swanepoel

Let $G$ be a graph with a vertex set $V$. The graph $G$ is path-proximinal if there are a semimetric $d \colon V \times V \to [0, \infty[$ and disjoint proximinal subsets of the semimetric space $(V, d)$ such that $V = A \cup B$, and…

General Topology · Mathematics 2023-03-07 Karim Chaira , Oleksiy Dovgoshey

We prove a far-reaching strengthening of Szemer\'edi's regularity lemma for intersection graphs of pseudo-segments. It shows that the vertex set of such a graph can be partitioned into a bounded number of parts of roughly the same size such…

Combinatorics · Mathematics 2023-12-05 Jacob Fox , Janos Pach , Andrew Suk

A class A of labelled graphs is bridge-addable if for all graphs G in A and all vertices u and v in distinct connected components of G, the graph obtained by adding an edge between u and u is also in A; the class A is monotone if for all G…

Combinatorics · Mathematics 2011-10-04 Louigi Addario Berry , Colin McDiarmid , Bruce Reed

The toughness of a graph $G$ is defined as the largest real number $t$ such that for any set $S\subseteq V(G)$ such that $G-S$ is disconnected, $S$ has at least $t$ times more elements than $G-S$ has components (unless $G$ is complete, in…

Combinatorics · Mathematics 2026-03-06 J. Pascal Gollin , Martin Milanič , Laura Ogrin

A geometric graph is a graph drawn in the plane so that its vertices and edges are represented by points in general position and straight line segments, respectively. A vertex of a geometric graph is called pointed if it lies outside of the…

Combinatorics · Mathematics 2022-08-31 Nikita Chernega , Alexandr Polyanskii , Rinat Sadykov